Primary Mandibular Second Molars Research Articles

Success Rate of Obturation of Root Canals by Different Techniques in Primary Molars: A Comparative Clinical Study

Objective: To compare the success rate of different obturation procedures in primary mandibular second molars clinically and also by digital radiovisiography. Methods: A total of 40 children aged between 4-8 years with deeply carious mandibular second primary molars indicated for single session pulpectomy were selected. Canals were obturated with Metapex. The 3 study groups (Endodontic plugger, Handheld lentulospiral, Navi Tip syringe) were compared with the control group (reamer) both clinically and radiovisiographically. The data collected were statistically analyzed using Pearson’s Chi-square and Fisher’s exact test. Results: The use of Navi tip syringe led to the least number of voids followed by Endodontic plugger and Reamer and the highest number of voids was reported with Lentulospiral. Navitip presented maximum number of optimally filled cases followed by Endodontic plugger and Lentulospiral and least number of optimally filled cases with reamer. However, there was no statistically significant difference (p>0.05) in any of the groups with clinical (pain and tenderness to percussion) and radiographic parameters (presence or absence of voids and length of obturation). Conclusion: Within the limitations of the present study, though the clinical outcome was statistically insignificant, Navitip syringe exhibited encouraging results and is a promising option for obturation in primary teeth.

Investigation of root and canal morphology of human primary mandibular second molar by cone-beam CT

To investigate the root and canal morphology of primary mandibular second molars in a Chinese population by cone-beam CT(CBCT). A total of 305 CBCT images of 305 children aged 4-8 years were collected, who came to West China Dental Hospital from October, 2011 to March, 2012 due to supernumerary teeth, dental trauma, orthodontic treatment or oral maxillofacial tumor. Primary mandibular second molars which roots were full developed, without periapical infection or apical root resorption were enrolled. All the images were analyzed by two researchers. The data were statistically analyzed by software SPSS 19.0. Four hundred and thirty-seven primary mandibular second molars(PMSM) showed single mesial root except one which had two. Three hundred and twenty-five (74.4%) teeth had one distal root, 111(25.4%) teeth had two and one had three. There were 424(97.0%) teeth which had two mesial canals and 13(3.0%) had one.One hundred and three(23.6%) teeth had one distal root with one canal, 222(50.8%) had one distal root with two canals, 106(24.3%) had two distal roots with two canals, 5(1.1%) had two roots with three canals and 1(0.2%) had three roots with three canals. The root canal system of PMSM had ten variants in this study. The prevalence of three-rooted PMSM had significant differences from different genders (P = 0.000) and different sides (P = 0.028). Majority of primary mandibular second molars had two roots, and the minority had three roots. The prevalence of three-rooted molars in males were higher than that in females. Mesial and distal roots of primary mandibular second molars often had two canals.

Evaluate root and canal morphology of primary mandibular second molars in Chinese individuals by using cone-beam computed tomography

More detailed knowledge of root and canal morphology is important in order to improve the success in the endodontics of primary teeth. The purpose of this study was to evaluate the root and canal morphology of primary mandibular second molars (PMSMs) in a Chinese population using cone-beam computed tomography (CBCT). CBCT images, which had been obtained previously in the West China Hospital of Stomatology at Sichuan University, Chengdu, China between May 2009 and December 2011, were screened retrospectively. Finally, 283 individuals-207 male and 76 female with a mean age of 7.2 years (range 3-10 years)-and 487 PMSMs with clear images of root and canal morphology were enrolled. The number of roots and morphology of canals were recorded. The patient's gender, and the symmetry and frequency of three roots in PMSMs were analyzed. The majority of PMSMs had two (72.28%) or three roots (27.52%). The symmetrical incidence of three-root PMSMs in this Chinese population was 50.65%. There is no difference between genders in the prevalence of an extra root and the incidence of symmetry (p>0.05). Of the individuals enrolled, 25.26% of PMSMs had three canals and 73.31% had four canals. The root canal systems of the PMSMs in the present study were categorized into seven variants. This study indicated that three-rooted PMSMs occur frequently in the Chinese population. There was no difference between the two genders on incidence and symmetry. The majority of PMSMs have three to four canals and the diversity of the root canal variants should be considered when performing clinical procedures. CBCT is a good option for studying the root and canal morphology of primary teeth.

Ectopic eruption of the first permanent molars: prevalence and etiologic factors.

The purpose of this research was to study the prevalence of ectopic eruption of the first permanent molars and possible etiologic factors. A group of 4,232 Thai students, from 6 to 9 years old, was examined. The prevalence of ectopic eruption of the first permanent molars in the subjects was 0.75%. Both the severity of the ectopic eruption and the amount of root resorption on the second primary molars were more pronounced in the maxilla than in the mandible. The important etiologic factors were the eruption path of the first permanent molars relative to reference lines and the size of the mandibular second primary molars. The amount of proximal caries did not seem to affect the prevalence of ectopic eruption.